在鎂合金的研究方面，為提升材料的成形性，有許多嘗試，使用大量塑性變形法來促使鎂合金晶粒細化。在大量塑性變形法中，等徑轉角擠製是最多元的加工法，藉由不同的擠製參數可以得到更多樣化的顯微結構。這些參數包括：擠製溫度、道次、路徑。從過去研究成果可知，AZ80鎂合金在經過八道次Bc路徑200℃製程擠製後的胚料，因差排過度集中，容易造成應力腐蝕，導致金相攝影時之晶粒界面模糊，使得顯微結構無法判別。本研究以AZ80鎂合金為對象，探討在大量塑性變形下上述加工參數對材料性質所造成的影響，其次，再利用退火熱處理的方式，藉由加熱溫度與持溫時間的控制，舒緩AZ80鎂合金因等徑轉角擠製而造成應力腐蝕的問題，然後從金相、拉伸試驗結果分析，期望能找出提升鎂合金胚料機械性質的最佳退火熱處理參數。
在各退火溫度下金相拍攝的結果顯示，250℃的退火溫度下，晶粒成長的速度很緩慢，顯微結構最佳，其次為300℃，而400℃的退火溫度下，晶粒成長的速度非常劇烈，已經失去等徑轉角擠製後晶粒細化的目的。由拉伸試驗的結果來看，晶粒細化後的擠製材和擠製後的退火材，與原素材比較延性有明顯的改善，在300℃、10-1S-1的條件下材料的伸長率最佳、證明晶粒細化能有效提升胚料的延性。

摘要 ii
ABSTRACT iii
誌謝 iv
目錄 v
表目錄 vii
圖目錄 viii
第一章 序論 1
1-1 研究背景 1
1-2 研究動機與內容 3
第二章 文獻回顧 8
2-1 鎂合金簡介 8
2-1-1 鎂合金命名方式 8
2-1-2 添加元素對鎂合金的影響 9
2-1-3 鎂合金的優點 12
2-2 退火 13
2-3 回復與再結晶 14
2-3-1 回復 14
2-3-2 再結晶 15
2-4 晶粒細化之影響 16
2-4-1 晶粒細化的方法 17
2-5 大量塑性變形法 18
2-5-1 等徑轉角擠製之介紹 19
2-5-2 等徑轉角擠製之變形原理 20
2-5-3 等徑轉角擠製之製程參數 22
2-6 其它連續大量塑性變形法 27
2-7 超塑性 30
2-7-1 超塑性的變形機構 30
2-7-2 超塑性材料的微觀特性 31
2-7-3 鎂合金的超塑性變形 33
第三章 實驗流程與規劃 46
3-1 實驗材料 48
3-2 實驗設備 48
3-3 實驗步驟 49
3-3-1 利用ECAE製做鎂合金胚料 50
3-3-2 退火熱處理 52
3-3-3 金相觀察 53
3-3-4 拉伸試驗 56
第四章 實驗結果與討論 70
4-1 金相觀察 70
4-1-1 鋁含量的多寡對於顯微結構的影響 70
4-1-2 退火熱處理參數對於顯微結構的影響 71
4-3 拉伸試驗分析 75
第五章 結論與未來展望 90
5-1 結論 90
5-2 未來展望 91
參考文獻 92

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